Horst,

A long time ago I posted a solution on how to enter quarter note triplets in the chord spread sheet. Perhaps if you enter Tonnie in the "Search Forums" window you might still find it.

I suggested that you divide a 4/4 quarter note bar into half and make the half you need for the triplets into a 3/4 (waltz) bar (with a style that mimics your 4/4 style, e.g. brushes etc.) and the remainder into a 2/4 (swing) bar.
Then there has to be made a change in tempo for the 3/4 bar, as 3 chords should take no longer than the 2/4 bar and then return to your original tempo after the 3/4 bar, in order to not disrupt the rhythm of your song.

At he time I tested it also with real styles!

Of course also the melody and soloist notes have to be entered as a waltz or altered in duration accordingly.

Good luck!

Tonnie